@inproceedings{DiermeierSindersbergerMonkman, author = {Diermeier, Andreas and Sindersberger, Dirk and Monkman, Gareth J.}, title = {Magneto-Active Polymer Actuator}, series = {Actuator 16 : 15th International Conference on New Actuators \& 9th International Exhibition on Smart Actuators and Drive Systems : conference proceedings}, booktitle = {Actuator 16 : 15th International Conference on New Actuators \& 9th International Exhibition on Smart Actuators and Drive Systems : conference proceedings}, publisher = {WFB}, address = {Bremen}, isbn = {978-3-933339-26-3}, pages = {286 -- 289}, abstract = {Magneto-active Polymers (MAP) are closely related to magneto-rheological fluids in that they contain magnetic micro-particles. However, instead of being freely suspended in a carrier fluid they are physically bound within a highly elastic polymer-matrix. The application of an external magnetic field allows changes in the mechanical properties, such as elastic and shear moduli, of the composite material to be achieved. The colossal magneto-rheological effect has been shown to demonstrate changes in Young's modulus by over 1E6 \%. Current research concentrates on controllable compliance and the resulting shape memory properties of MAP. This paper deals with recent advancements in this respect, including tubular magneto-active devices with potential applications in medical and other technology.}, language = {en} } @article{MonkmanBoody, author = {Monkman, Gareth J. and Boody, F. P.}, title = {Ein Vergleich verschiedene Master-Programme}, series = {Die Neue Hochschule}, journal = {Die Neue Hochschule}, number = {1}, publisher = {DUZ Verlags- und Medienhaus GmbH}, address = {Berlin}, pages = {12 -- 13}, language = {de} } @article{DillingerMayerSchneideretal., author = {Dillinger, Andrea Elisabeth and Mayer, Matthias and Schneider, Magdalena and Weber, Gregor R. and Goeppner, Corinna and Tamm, Ernst R. and Shamonin (Chamonine), Mikhail and Monkman, Gareth J. and Fuchshofer, Rudolf}, title = {Reactive changes in optic nerve astrocytes are mediated by CTGF, TGF beta 2 and increasing substratum stiffness}, series = {Investigative ophthalmology \& visual science}, volume = {56}, journal = {Investigative ophthalmology \& visual science}, number = {7}, publisher = {ASSOC RESEARCH VISION OPHTHALMOLOGY INC}, abstract = {Purpose: Patients with primary open-angle glaucoma (POAG) show a stiffer peripapillary sclera, reactive astrocytes and a remodeled lamina cribrosa (LC). The changes are thought to be mediated by TGFβ2 and its downstream mediator CTGF. Recently we developed a murine glaucoma model by overexpressing CTGF in the anterior eye (βb1CTGF). In this study we investigated the glial lamina region of βb1CTGF mice, and the changes of astrocytes in response to CTGF and TGFβ2 as well as increasing substratum stiffness. Methods: Tangential sections of the glial LC of 2-month-old βb1CTGF mice and their wild-type littermates (WT) were stained with phalloidin and antibodies against GFAP, CTGF and fibronectin (FN). Murine optic nerve (ON) astrocytes from CD1 mice were isolated, cultured and characterized by GFAP staining. The astrocytes were treated with TGFβ2 (1ng/ml) and CTGF (50ng/ml and 100ng/ml). In addition, the cells were seeded on PDMS substrata with different stiffness (10, 30 and 60 kPa). Treated cells were analyzed by Western blotting, real-time RT-PCR and immunohistochemistry. Wound healing assays were performed to analyze migration rate following growth factor treatment. Results: βb1CTGF mice showed a massive increase in CTGF and GFAP in the glial LC when compared with WT mice. Moreover, an increase in FN staining and phalloidin-labeled actin was observed in the peripapillary sclera. Murine ON astrocytes reacted on increased substrate stiffness by increasing the synthesis of GFAP, vimentin and CTGF. Treatment of the cells with TGFβ2 and CTGF led to an enhanced migration rate. In addition, treatment resulted in an increased expression and synthesis of ECM proteins, including FN, tropoelastin, collagen type I and III. The in vitro findings correlated with those seen in the glaucoma mouse model. Conclusions: We conclude that changes in the ECM of LC and peripapillary sclera alter their biomechanical properties and thereby induce reactive changes in resident astrocytes. The reactive changes induced by higher stiffness of their surrounding ECM give rise to a self-amplifying process that includes increased TGFβ2/CTGF signaling and leads to synthesis of ECM and cytoskeletal proteins, a process that in turn augments the stiffness at the optic nerve head (ONH). Such a scenario may finally result in a vicious circle as the causative mechanism for ONH deformation in POAG.}, language = {en} } @article{SorokinStepanovShamoninChamonineetal., author = {Sorokin, Vladislav V. and Stepanov, Gennady V. and Shamonin (Chamonine), Mikhail and Monkman, Gareth J. and Khokhlov, Alexei R. and Kramarenko, Elena Yu}, title = {Hysteresis of the viscoelastic properties and the normal force in magnetically and mechanically soft magnetoactive elastomers: Effects of filler composition, strain amplitude and magnetic field}, series = {Polymer}, volume = {76}, journal = {Polymer}, publisher = {Elsevier}, doi = {10.1016/j.polymer.2015.08.040}, pages = {191 -- 202}, abstract = {Hysteresis in dynamic modulus, loss factor and normal forces of magnetoactive elastomers (MAEs) comprising various proportions of small (3-5 mu m) and large (50-60 mu m) ferromagnetic particles are experimentally studied using dynamic torsion performed at a fixed oscillation frequency in varying DC magnetic fields. It is shown that hysteresis is a characteristic feature of MAEs observed both under increasing/decreasing magnetic field strength and increasing/decreasing strain amplitude. This hysteresis is attributed to the specific rearrangement of the magnetic filler network under simultaneously applied magnetic field and shear deformation. Rheological properties of the magnetic filler network formed in the magnetic field and, therefore, the rheological properties of MAEs depend strongly on the filler composition and the magnetic field magnitude. Larger magnetic particles and higher magnetic fields provide stronger magnetic networks. Both factors result in the extension of the linear viscoelastic regime to larger strain amplitudes and lead to higher values of shear storage and loss moduli. It is found that the hysteresis width maximises at an intermediate magnetic field where it is attributed to the balance between elastic and magnetic particle interactions. This is apparently where the most significant restructuring of the magnetic network occurs. The hysteresis width decreases with increasing fraction of large particles in the magnetic filler. The loss factor grows significantly when the magnetic network is physically broken by large strains gamma > 1\%. A huge (more than one order of magnitude) increase of normal force at maximum magnetic field strengths is observed. It is predicted that any physical quantity depending on the internal structuring of the magnetic filler should demonstrate hysteresis either with a changing magnetic field and constant deformation amplitude or under variable deformation in a constant magnetic field. (C) 2015 Elsevier Ltd. All rights reserved.}, language = {en} } @article{MonkmanSindersbergerDiermeieretal., author = {Monkman, Gareth J. and Sindersberger, Dirk and Diermeier, Andreas and Prem, Nina}, title = {The magnetoactive electret}, series = {smart materials and structures}, volume = {26}, journal = {smart materials and structures}, number = {7}, publisher = {IOP Publishing}, doi = {10.1088/1361-665X/aa738f}, abstract = {A magnet which adheres to every surface, not only those of ferromagnetic materials, has hitherto been the domain of science fiction. Now for the first time such a novel device exists. The fusion of a permanently magnetized magnetoactive polymer containing hard magnetic particles and an electret enhanced with ferroelectric particles has resulted in the development of a new smart device-the magnetoactive electret. Magnetoactive electrets can be made to exhibit the usual magnetic properties of permanent magnetism together with the electrostatic properties of electrets. This results in simultaneous magnetoadhesion and electroadhesion forces from the same elastomeric element. The biasing field, needed to avoid discontinuities concerned with transition through the zero point in operating curves, is normally provided by means of either a magnetic or an electric field. This novel technology provides both bias options in a single device.}, language = {en} } @article{MonkmanSindersbergerPremetal., author = {Monkman, Gareth J. and Sindersberger, Dirk and Prem, Nina and Diermeier, Andreas and Szecsey, Tamara}, title = {Dielectric behaviour of magnetic hybrid materials}, series = {Physical Sciences Reviews}, volume = {7}, journal = {Physical Sciences Reviews}, number = {10}, publisher = {de Gruyter}, doi = {10.1515/psr-2019-0121}, pages = {1169 -- 1185}, abstract = {The objectives of this work include the analysis of electrical and magnetic properties of magneto-elastic hybrid materials with the intention of developing new techniques for sensor and actuator applications. This includes the investigation of dielectric properties at both low and high frequencies. The behaviour of capacitors whose dielectrics comprise magnetic hybrid materials is well known. Such interfacial magnetocapacitance can be varied according to magnetic content, magnetic flux density and the relative permittivity of the polymer matrix together with other dielectric content. The basic function of trapping electrical charges in polymers (electrets) is also established technology. However, the combination of magnetoactive polymers and electrets has led to the first electromagnetic device capable of adhering to almost any material, whether magnetically susceptible or not. During the course of this research, in addition to dielectrics, electrically conductive polymers based on (PDMS) matrices were developed in order to vary the electrical properties of the material in a targeted manner. In order to ensure repeatable results, this demanded new fabrication techniques hitherto unavailable. The 3D printing of silicones is far from being a mature technology and much pioneering work was necessary before extending the usual 3 d.o.f. to include orientation about and diffusion of particles in these three axes, thus leading to the concept of 6D printing. In 6D printing, the application of a magnetic field can be used during the curing process to control the particulate distribution and thus the spatial filler particle density as desired. Most of the devices (sensors and actuators) produced by such methods contain levels of carbonyl iron powder (CIP) embedded magnetic filler of up to 70 wt\%. Contrary to this, a hitherto neglected research area, namely magnetoactive polymers (MAPs) having significantly lower magnetic particle concentrations (1 to 3 wt\% CIP) were also investigated. With filler concentrations lower than 3 wt\%, structures are formed which are completely absent at higher filler levels. CIP concentrations in the range of 1wt\% demonstrate the formation of toroidal structures. Further development of coherent rings with a compact order results as filler concentrations increase towards 2 wt\%. Above 3 wt\% the structure eventually disintegrates to the usual random order found in traditional MAP with higher CIP content. Structured samples containing 1\%-3 wt\% CIP were investigated with the aid of X-ray tomography where solitary ring structures can be observed and eventually the formation of capillary doubles. Over wavelengths ranging from 1 to 25 µm, spectroscopic analysis of thin film MAP samples containing 2 wt\% CIP revealed measurable magnetic-field-dependent changes in IR absorption at a wavenumber 2350 (λ = 4.255 µm). This was found to be due to the diamagnetic susceptibility of atmospheric carbon dioxide (CO2). Consequently, the first potential application for sparse matrix MAPs was found.}, language = {en} } @article{PremSindersbergerMonkman, author = {Prem, Nina and Sindersberger, Dirk and Monkman, Gareth J.}, title = {Mini-Extruder for 3D Magnetoactive Polymer Printing}, series = {Advances in Materials Science and Engineering}, journal = {Advances in Materials Science and Engineering}, publisher = {HINDAWI}, doi = {10.1155/2019/8715718}, pages = {1 -- 8}, abstract = {This work describes the development of a new miniature extruder, essential to cavity-free 3D printing of silicone-based smart materials. This makes the 3D printing of magnetoactive and electroactive polymer soft robotic components and devices directly from CAD data possible. The special feature of such an extruder is that it is designed for use with addition-crosslinking RTV-2 silicones, including solid particulate additives. The extruder merges the respective components automatically during extrusion which obviates the need for premixing and vacuum evacuation. Problems associated with inhomogeneities and unwanted cavity production are consequently eliminated. Rheological details necessary to the design, together with some preliminary performance results, are presented.}, language = {en} } @article{KreitmeierChashinFetisovetal., author = {Kreitmeier, Florian and Chashin, Dmitri V. and Fetisov, Yuri K. and Fetisov, Leonid Y. and Schulz, Irene and Monkman, Gareth J. and Shamonin (Chamonine), Mikhail}, title = {Nonlinear Magnetoelectric Response of Planar Ferromagnetic-Piezoelectric Structures to Sub-Millisecond Magnetic Pulses}, series = {Sensors}, volume = {12}, journal = {Sensors}, number = {11}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/s121114821}, pages = {14821 -- 14837}, abstract = {The magnetoelectric response of bi- and symmetric trilayer composite structures to pulsed magnetic fields is experimentally investigated in detail. The structures comprise layers of commercially available piezoelectric (lead zirconate titanate) and magnetostrictive (permendur or nickel) materials. The magnetic-field pulses have the form of a half-wave sine function with duration of 450 µs and amplitudes ranging from 500 Oe to 38 kOe. The time dependence of the resulting voltage is presented and explained by theoretical estimations. Appearance of voltage oscillations with frequencies much larger than the reciprocal pulse length is observed for sufficiently large amplitudes (~1-10 kOe) of the magnetic-field pulse. The origin of these oscillations is the excitation of bending and planar acoustic oscillations in the structures. Dependencies of the magnetoelectric voltage coefficient on the excitation frequency and the applied magnetic field are calculated by digital signal processing and compared with those obtained by the method of harmonic field modulation. The results are of interest for developing magnetoelectric sensors of pulsed magnetic fields as well as for rapid characterization of magnetoelectric composite structures.}, language = {en} } @article{MonkmanSindersbergerPremetal., author = {Monkman, Gareth J. and Sindersberger, Dirk and Prem, Nina and Szecsey, Tamara}, title = {Smart Stiction}, series = {Robotics \& Automation Engineering Journal}, volume = {4}, journal = {Robotics \& Automation Engineering Journal}, number = {4}, publisher = {Juniper Publishers}, doi = {10.19080/RAEJ.2019.04.555641}, abstract = {Soft robotics could loosely be described as the engineering science of expanded dexterity through controllable flexibility. The exploitation of controllable compliance through the judicious choice of soft flexible members, as opposed to a finite number of rigid kinematic joints, can result in greater dexterity without compromising simplicity. One example is the replacement of segmented mechanical legs with simple compliant material eruciform prolegs. To achieve this in robotics, without introducing additional mechanical joints, mobile surfaces with switchable coefficients of friction is essential. This paper explains how, using silicone based smart materials, the rapid alternation between kinematic and static friction (stiction) may be achieved.}, language = {en} } @article{SindersbergerPremMonkman, author = {Sindersberger, Dirk and Prem, Nina and Monkman, Gareth J.}, title = {Structure formation in low concentration magnetoactive polymers}, series = {AIP advances}, volume = {9}, journal = {AIP advances}, number = {3}, publisher = {AIP Publishing}, doi = {10.1063/1.5079997}, abstract = {This paper concerns recent research into the autonomous formation of micro-structures in low carbonyl iron powder (CIP) concentration magneto active polymers (MAP). Higher concentrations of CIP show an isotropic distribution of magnetic filler throughout the entire sample, while autonomous structure formation is possible at mass concentrations lower than 3\%. The formation of micro-toroids commences as CIP concentration approaches 1\% wt. Further development of coherent rings with a defined order follow as CIP concentrations increase toward 2\% wt, whilst exceeding 3\% wt leads to the same isotropic distribution found in higher concentration MAP. Structured samples containing between 1\% wt and 3\% wt CIP were investigated using X-Ray tomography where solitary structures could clearly be observed. The ring structures represent microinductivities whose geometries can be manipulated during fabrication. In addition, these structures are magnetic field sensitive. This is not only relevant to applications in the GHz and THz areas but recent research has revealed implications for optical, thermal, acoustic and even chemical MAP sensors. (C) 2019 Author(s).}, language = {en} } @article{ChenZhangSongetal., author = {Chen, Rui and Zhang, Zhuo and Song, Ruizhou and Fang, Cheng and Sindersberger, Dirk and Monkman, Gareth J. and Guo, Jianglong}, title = {Time-dependent electroadhesive force degradation}, series = {Smart Materials and Structures}, volume = {29}, journal = {Smart Materials and Structures}, number = {5}, publisher = {IOP Publishing}, doi = {10.1088/1361-665X/ab79b5}, abstract = {This paper concerns a comprehensive investigation of time-dependent electroadhesion (EA) force degradation. EA shear force tests on different object materials (a PET, glass, ABS, and wood plate) have shown that force degradation was dominated by residual polarization charges trapped in the EA pad dielectric rather than in the substrate dielectric from which the object to be prehended is made. In order to explain this dynamic physical phenomenon, a model of dielectric polarization and depolarization has been proposed. According to the derived relationship between EA force and discharge time, three different methods intended to mitigate this problem has been compared: (1) the natural discharge method, (2) the high voltage resistor discharge method, and (3) the discharge prior to field polarity reversal method. These methods are useful for generating repeatable and stable EA forces, which are required for the characterization of EA pads and their subsequent employment in material handling, mobile robot crawling and climbing tasks.}, language = {en} } @article{SchmidtStraubSindersbergeretal., author = {Schmidt, Henrik and Straub, Benedikt B. and Sindersberger, Dirk and Br{\"o}ckel, Ulrich and Monkman, Gareth J. and Auernhammer, G{\"u}nter}, title = {Collision and separation of nickel particles embedded in a Poly dimethylsiloxan matrix under a rotating magnetic field: A strong magneto active function}, series = {Colloid and Polymer Science}, volume = {299}, journal = {Colloid and Polymer Science}, publisher = {Springer}, doi = {10.1007/s00396-020-04784-4}, pages = {955 -- 967}, abstract = {In order to function as soft actuators, depending on their field of use, magnetorheological elastomers (MREs) must fulfill certain criteria. To name just a few, these can include rapid response to external magnetic fields, mechanical durability, mechanical strength, and/or large deformation. Of particular interest are MREs which produce macroscopic deformation for small external magnetic field variations. This work demonstrates how this can be achieved by just a small change in magnetic field orientation. To achieve this, (super)paramagnetic nickel particles of size ≈ 160 μm were embedded in a non-magnetic polydimethylsiloxan (PDMS) (661-1301 Pa) and their displacement in a stepwise rotated magnetic field (170 mT) recorded using a video microscope. Changes in particle aggregation resulting from very small variations in magnetic field orientation led to the observation of a new strongly magneto-active effect. This configuration is characterized by an interparticle distance in relation to the angle difference between magnetic field and particle axis. This causes a strong matrix deformation which in turn demonstrates hysteresis on relaxation. It is shown that the occurrence strongly depends on the particle size, particle distance, and stiffness of the matrix. Choosing the correct parameter combination, the state can be suppressed and the particle-matrix system demonstrates no displacement or hysteresis. In addition, evidences of non-negligible higher order magnetization effects are experimentally ascertained which is qualitatively in agreement with similar, already theoretically described, particle systems. Even at larger particle geometries, the new strongly magneto-active configuration is preserved and could create macroscopic deformation changes.}, language = {en} } @inproceedings{SeflProchazkaHalleretal., author = {Sefl, Ondrej and Prochazka, Radek and Haller, Rainer and Monkman, Gareth J.}, title = {Alternative Approach to Optical Detection of Partial Discharges in Air}, series = {2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP): 12-15 Dec. 2021, Vancouver, BC, Canada}, booktitle = {2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP): 12-15 Dec. 2021, Vancouver, BC, Canada}, publisher = {IEEE}, isbn = {978-1-6654-1907-9}, issn = {2576-2397}, doi = {10.1109/CEIDP50766.2021.9705350}, pages = {324 -- 327}, abstract = {This article compares the standard electrical method of partial discharge detection with a novel optical detection method based on silicon photomultipliers. A third, complementary, single-loop antenna method is added to represent the ultra-high frequency method commonly used in gas-insulated switchgear/lines. A trio of air-insulated electrode designs that simulate the fundamental fault/discharge types in gaseous insulation (protrusion - corona discharge, floating conductive particle, surface discharges) are employed. Phase-resolved partial discharge activity patterns are compiled for each electrode design. The patterns are analyzed using spatial statistics and the interpretation of the obtained data trends explained by means of an example. Ultimately, the consistency and reliability of discharge detection by the optical methods for each fault/discharge type are evaluated, and suggestions for improvement are made.}, language = {en} } @inproceedings{SindersbergerPremMonkmanetal.2021, author = {Sindersberger, Dirk and Prem, Nina and Monkman, Gareth J. and Zimmermann, Klaus}, title = {Self-Sensing Electroadhesive Polymer Gripper with Magnetically Controllable Surface Geometry}, series = {Actuator 2021, International Conference and Exhibition on New Actuator Systems and Applications: GMM conference, February 17-19, 2021, online event}, booktitle = {Actuator 2021, International Conference and Exhibition on New Actuator Systems and Applications: GMM conference, February 17-19, 2021, online event}, editor = {Schlaak, Helmut}, publisher = {VDE VERLAG}, address = {Berlin; Offenbach}, isbn = {9783800754540}, doi = {10.1002/macp.201800222}, pages = {318 -- 320}, year = {2021}, abstract = {Compared to conventional end effectors, electro-adhesive grippers enable the handling of sensitive, soft or air-permeable materials [1]. The prehension force is based on a strong electric field generated by electrodes resulting in a polarisation of the dielectric and the generation of mirror charges in the workpiece. When the electrode supply voltage is deactivated, the electric field drops,but an electrostatic field remains due to remanent polarisation of the dielectric. The residual charge on the gripper surface reduces only slowly and in combination with other influencing factors can prevent the workpieces from being ejected temporarily or completely. In this work a solution to this problem is presented by means of gripper surface deforming caused by the applicat ion of a magnetic field to a magneto- active polymer (MAP) actuator. The in-creased distance between the workpiece and the dielectric enables precise and controlled ejection. In addition to compliance and deformability, the employment of soft smart materials enables the integration of self-sens-ing mechanisms for the measurement of surface deformation. The embedding of electrically conductive flexible electrodes within the soft silicone dielectric sup port such movements and serves as the n ecessary electrodes for electroadhesion. Since the implementation of the end effectoris based entirely on soft materials, the self-sensing magnetically controllable electroadhesive gripper (SMEG) can be produced in a shape deposition manufacturing (SDM) process [2], [3] and is highly applicable to the field of soft robotics.}, language = {de} } @article{SorokinEckerStepanovetal., author = {Sorokin, Vladislav V. and Ecker, Eva and Stepanov, Gennady V. and Shamonin (Chamonine), Mikhail and Monkman, Gareth J. and Kramarenko, Elena Yu and Khokhlov, Alexei R.}, title = {Experimental study of the magnetic field enhanced Payne effect in magnetorheological elastomers}, series = {Soft Matter}, volume = {10}, journal = {Soft Matter}, number = {43}, publisher = {ROYAL Society of CHEMISTRY}, doi = {10.1039/c4sm01738b}, pages = {8765 -- 8776}, abstract = {The dynamic modulus and the loss factor of magnetorheological elastomers (MREs) of various compositions and anisotropies are studied by dynamic torsion oscillations performed in the absence and in the presence of an external magnetic field. The emphasis is on the Payne effect, i.e. the dependence of the elastomer magnetorheological characteristics on the strain amplitude and their evolution with cyclically increasing and decreasing strain amplitudes. MREs are based on two silicone matrices differing in storage modulus (soft, G' similar to 10(3) Pa, and hard, G' similar to 10(4) Pa, matrices). For each matrix, the concentration of carbonyl iron particles with diameters of 3-5 mu m was equal to 70 and 82 mass\% (22 and 35 vol\%, respectively) in the composite material. Samples for each filler content, isotropic and aligned-particles, are investigated. It is found that the Payne effect significantly increases in the presence of an external magnetic field and varies with the cyclical loading which reaches saturation after several cycles. The results are interpreted as the processes of formation-destruction-reformation of the internal filler structure under the simultaneously applied mechanical force and magnetic field. Impacts of matrix elasticity and magnetic interactions on the filler alignment are elucidated.}, language = {en} } @article{ChenSongZhangetal., author = {Chen, Rui and Song, Ruizhou and Zhang, Zhuo and Bai, Long and Liu, Fuqiang and Jiang, Pei and Sindersberger, Dirk and Monkman, Gareth J. and Guo, Jianglong}, title = {Bio-Inspired Shape-Adaptive Soft Robotic Grippers Augmented with Electroadhesion Functionality}, series = {Soft Robotics}, volume = {6}, journal = {Soft Robotics}, number = {6}, publisher = {Mary Ann Liebert}, doi = {10.1089/soro.2018.0120}, pages = {701 -- 712}, abstract = {Soft robotic grippers (SRGs) have been extensively employed in robotic grasping and manipulation applications due to the fact that they are beneficial for pick-and-place of difficult-to-handle and delicate objects with various geometries and stiffness in a comfortable and safer way. This article presents a bio-inspired and shape-adaptive SRG augmented with electroadhesion (EA) functionality, FinEA, by a cost-effective combination of a Fin Ray structured two-fingered SRG with two soft-stretchable EA pads. The EA pads were manufactured by screen printing a layer of electrically conductive and elastomeric carbon black powder mixed with polydimethylsiloxane onto a dielectric substrate. The compliant Fin Ray fingers, composed of soft longitudinal beams and rigid cross beams, were structurally optimized by the finite element method using ABAQUS/CAE based on three key parameters: the open angle of the longitudinal beams, the spacing between the cross beams, and the incline angle of the cross beams. The soft beams were produced by a traditional soft lithography method, whereas the rigid cross beams were three-dimensionally printed. The resultant FinEA grippers were capable of lifting not only flat/thin materials without distorting them due to the employment of EA, but also concave and convex objects due to the passively shape-adaptive Fin Ray structure and the EA functionality. In addition, the proposed FinEA grippers were able to grasp delicate materials and objects whose diameters are larger than the overall gripper length. Furthermore, 65\% more weight in shear were picked up by the FinEA gripper when 4 kV was applied compared with 0 V. The FinEA concept provides useful and alternative solution for controllable adhesion-based SRGs and may facilitate the inspiration and development of future SRGs with added functionality and enhanced versatility.}, language = {en} } @article{DiermeierSindersbergerAngeleetal., author = {Diermeier, Andreas and Sindersberger, Dirk and Angele, Peter and Kujat, Richard and Monkman, Gareth J.}, title = {Sensor system for use with low intensity pulsed ultrasound}, series = {Sensor review}, volume = {39}, journal = {Sensor review}, number = {6}, publisher = {Emerald}, issn = {0260-2288}, doi = {10.1108/SR-11-2018-0304}, pages = {828 -- 834}, abstract = {Purpose Ultrasound is a well-established technology in medical science, though many of the conventional measurement systems (hydrophones and radiation force balances [RFBs]) often lack accuracy and tend to be expensive. This is a significant problem where sensors must be considered to be "disposable" because they inevitably come into contact with biological fluids and expense increases dramatically in cases where a large number of sensors in array form are required. This is inevitably the case where ultrasound is to be used for the in vitro growth stimulation of a large plurality of biological samples in tissue engineering. Traditionally only a single excitation frequency is used (typically 1.5 MHz), but future research demands a larger choice of wavelengths for which a single broadband measurement transducer is desirable. Furthermore, because of implementation conditions there can also be large discrepancies between measurements. The purpose of this paper deals with a very cost-effective alternative to expensive RFBs and hydrophones. Design/methodology/approach Utilization of cost-effective piezoelectric elements as broadband sensors. Findings Very effective results with equivalent (if not better) accuracy than expensive alternatives. Originality/value This paper concentrates on how very cost-effective piezoelectric ultrasound transducers can be implemented as sensors for ultrasound power measurements with accuracy as good, if not better than those achievable using radiation force balances or hydrophones.}, language = {en} } @article{SindersbergerPremMonkman, author = {Sindersberger, Dirk and Prem, Nina and Monkman, Gareth J.}, title = {Self-assembling structure formation in low-density magnetoactive polymers}, series = {Journal of Applied Polymer Science}, volume = {137}, journal = {Journal of Applied Polymer Science}, number = {3}, publisher = {Wiley}, doi = {10.1002/app.48291}, abstract = {The formation of microstructures in magnetoactive polymers (MAPs) is a recently discovered phenomenon found only with very low filler particle concentrations (less than 3 wt \%). Due to the degassing process, filler particles collect around an ascending bubble, which dissolves at a certain point leaving particulate rings within the matrix. The formation of toroidal microstructures commences as filler concentration approaches 1 wt \%. The development of coherent parallel aligned rings with a compact order continues as particle concentrations increase toward 2 wt \%. Between 2 and 3 wt \% capillary doublets develop, while mass percentages higher than 3\% result in increasing entropy as the random order of particle agglomeration found in higher concentration MAP dominates. Self-structured samples of different filler material and concentrations between 1 and 3 wt \% have been investigated using X-ray tomography, where the emerging structures can be observed and visualized. The ring structures resulting from this research represent microinductivities which can be fabricated in a targeted manner, thus enabling new applications in the high-frequency radio field. Furthermore, these anisotropic, but well-organized, structures have magnetic field-dependent implications for optical, thermal, acoustic, and medical applications.}, language = {en} } @inproceedings{EgersdoerferZeidlerWieseretal., author = {Egersd{\"o}rfer, Stefan and Zeidler, A. and Wieser, A. and Trompier, F. and Monkman, Gareth J. and Shamonin (Chamonine), Mikhail}, title = {A portable accident dosimeter using tooth enamel}, series = {Proceedings of the 7th International Symposium on EPR Dosimetry and Applications and the 2nd International Conference on Biodosimetry held at the Uniformed Services University of the Health Sciences, Bethesda, MD, USA, 10-13 July 2006}, booktitle = {Proceedings of the 7th International Symposium on EPR Dosimetry and Applications and the 2nd International Conference on Biodosimetry held at the Uniformed Services University of the Health Sciences, Bethesda, MD, USA, 10-13 July 2006}, publisher = {Pergamon}, address = {Oxford}, language = {en} } @book{MonkmanHesseSteinmannetal., author = {Monkman, Gareth J. and Hesse, Stefan and Steinmann, Ralf and Schunk, Henrik}, title = {Robot Grippers}, publisher = {Wiley}, isbn = {9783527406197}, doi = {10.1002/9783527610280}, abstract = {Since robotic prehension is widely used in all sectors of manufacturing industry, this book fills the need for a comprehensive, up-to-date treatment of the topic. As such, this is the first text to address both developers and users, dealing as it does with the function, design and use of industrial robot grippers. The book includes both traditional methods and many more recent developments such as micro grippers for the optolectronics industry. Written by authors from academia, industry and consulting, it begins by covering the four basic categories of robotic prehension before expanding into sections dealing with endeffector design and control, robotic manipulation and kinematics. Later chapters go on to describe how these various gripping techniques can be used for a common industrial aim, with details of related topics such as: kinematics, part separation, sensors, tool excahnge and compliance. The whole is rounded off with specific examples and case studies. With more than 570 figures, this practical book is all set to become the standard for advanced students, researchers and manufacturing engineers, as well as designers and project managers seeking practical descriptions of robot endeffectors and their applications.}, language = {en} } @article{SorokinStepanovShamoninChamonineetal., author = {Sorokin, Vladislav V. and Stepanov, Gennady V. and Shamonin (Chamonine), Mikhail and Monkman, Gareth J. and Kramarenko, Elena Yu}, title = {Magnetorheological behavior of magnetoactive elastomers filled with bimodal iron and magnetite particles}, series = {Smart materials and structures}, volume = {26}, journal = {Smart materials and structures}, number = {3}, publisher = {IOP Publishing}, doi = {10.1088/1361-665X/26/3/035019}, abstract = {Magnetoactive elastomers (MAE) based on soft silicone matrices, filled with various proportions of large diameter ( approximately 50 mu m) iron and small diameter ( approximately 0.5 mu m) magnetite particles are synthesized. Their rheological behavior in homogeneous magnetic fields up to 600 mT is studied in detail. The addition of small magnetite particles facilitates fabrication of uniformly distributed magnetic elastomer composites by preventing aggregation and sedimentation of large particles during curing. It is shown that using the proposed bimodal filler particles it is possible to tailor various magnetorheological (MR) properties which can be useful for different target applications. In particular, either absolute or relative magnetorheological effects can be tuned. The value of the damping factor as well as the range of deformation amplitudes for the linear viscoelastic regime can be chosen. The interdependencies between different MR properties of bimodal MAEs are considered. The results are discussed in the model framework of particle network formation under the simultaneous influence of external magnetic fields and mechanical deformation.}, language = {en} } @article{SindersbergerDiermeierPremetal., author = {Sindersberger, Dirk and Diermeier, Andreas and Prem, Nina and Monkman, Gareth J.}, title = {Printing of hybrid magneto active polymers with 6 degrees of freedom}, series = {Materials today communications}, volume = {15}, journal = {Materials today communications}, number = {June}, publisher = {Elsevier}, doi = {10.1016/j.mtcomm.2018.02.032}, pages = {269 -- 274}, abstract = {3D printing techniques offer a versatile method for the fabrication and structuring of magnetoactive polymer (MAP) components and devices for research prototype development. MAP materials enjoy an advantage in that the particulate content may be manipulated by external magnetic fields during the forming and curing processes. Controlled particle diffusion within the polymer matrix, by means of external fields applied during the printing process, influences a further three spatial dimensions. This permits control of the spatial particle concentration and makes free displacement of particle accumulations possible during the crosslinking phase. Particles which are susceptible to electric or magnetic fields can thereby be shifted into regions previously free of particles. The additional 3 graded dispersion axes effectively results in what can be described as 6 degrees of freedom (6DOF) printing. Electrically conductive polymers combined with non-conductive areas, provide an additional benefit for the production of complex hybrid structures. This may be augmented by the combination of magnetically active thermoplastics as inelastic structural components together with mechanically deformable elastomers. The combination of all fabrication methods in one hybrid printing process makes the production of complex sensor and actuator systems in one manufacturing sequence possible. This far exceeds the capabilities of conventional casting and machining operations and opens new possibilities for the fabrication of soft material elements.}, language = {en} }